# -*- coding:utf-8 -*-
"""
Created on 2010-2-23

@author: madlee
"""

class Entity:
    def __init__(self):
        pass
    
    def __unicode__(self):
        raise NotImplementedError()

    def save(self, target):
        raise NotImplementedError()
    
    def load(self, source):
        raise NotImplementedError()
    
class Relation:
    def __init__(self):
        pass

class Person(Entity):
    pass

class Address(Entity):
    pass

class Organize(Entity):
    pass
